This invention relates in general to vehicle brake systems and in particular to a compliant torque coupler for use with a dual acting plunger assembly of such vehicle brake systems.
An automotive vehicle typically includes a hydraulic brake system for slowing and stopping the vehicle. The brake system typically includes a brake pedal operated by a driver of the vehicle, a master cylinder that generates hydraulic brake pressure when the brake pedal is depressed by the driver, and fluid conduits arranged in brake circuits that carry the brake pressure to wheel brakes. The brake system also typically includes a brake booster which increases the brake pressure generated by the master cylinder when the brake pedal is depressed.
The brake system may also include an anti-lock braking system (ABS) that monitors wheel rotation and selectively applies and relieves the brake pressure to maintain wheel speed and achieve maximum braking force. The ABS includes control valves for the purpose of applying and relieving the brake pressure—i.e., the control valves allow selective brake actuation. The selective brake actuation allowed by the control valves may also be used to implement an electronic stability control (ESC) system to improve vehicle stability.
An integrated brake control (IBC) system may be used to replace the ESC system along with the vacuum booster and any associated components such as cables, sensors, switches, electronic controllers, and vacuum pumps with a single integrated unit. The IBC system uses a dual acting plunger (DAP) assembly for a second source of brake pressure, independent from the master cylinder. Pressure generated by the DAP assembly may provide the ESC system functionality. The DAP assembly generates the hydraulic pressure using a ball screw assembly driven by an electric motor.
As is known to those skilled in the art, the ball screw assembly produces translational movement because of an external rotational restraint. For example, the rotational restraint may be a tab on the ball nut assembly inserted into a slot in a housing of the DAP assembly. However, the tab in slot restraint produces noise, vibration, and harshness when the motor reverses direction or is parked, pressure spikes in the ABS, or a sudden pressure release occurs. Therefore it would be desirable to have a DAP assembly with reduced noise, vibration, and harshness.